public async Task <ValidateProductCategoriesResponse> Validate(ValidateProductCategoriesRequest request) { var pairs = request.Pairs .Select(p => _convertService.Convert <ProductAndCategoryPairContract, ProductAndCategoryPair>(p)) .ToList(); var errorMessages = await _productCategoriesService.Validate(pairs); var response = new ValidateProductCategoriesResponse() { ErrorMessages = errorMessages, }; return(response); }